1. Field of the Invention
The invention relates to a method for assembling a wheel bearing apparatus used in a vehicle such as an automobile.
2. Description of Related Art
In a wheel bearing apparatus used in a vehicle such as an automobile, lubricant such as grease is provided in bearing inner space between an outer ring member and an inner ring member. In the case where muddy water or foreign matter intrudes into the bearing inner space, the degradation of grease, the formation of the rust of components, and reduction in the service life of bearing are caused. Therefore, in order to prevent the grease from leaking from the bearing inner space and prevent muddy water or foreign matter from intruding into the bearing inner space from an outside, the wheel bearing apparatus is provided with a sealing unit.
As a sealing unit for a wheel bearing apparatus, a hub seal commonly called a pack seal has been known. The hub seal includes a sealing member and a slinger. The sealing member is fixed at an opening at the end of the outer ring member. The sealing member includes at least two sealing lips including a side lip and a radial lip. The slinger is fixed to the slinger fitting face of the inner ring member. The slinger has an L-shaped section, and includes a cylindrical portion and a flat-plate portion (see Japanese Patent Application Publication No. 2005-291485 (JP 2005-291485 A)).
The side lip of the hub seal is in slide contact with the lateral face of the flat-plate portion of the slinger on the side of the bearing inner space, while the radial lip of the hub seal is slide contact with the outer periphery of the cylindrical portion of the slinger. The sealing member and the slinger are attached at the opening of the bearing inner space between the outer ring member and the inner ring member such that the end of the sealing member on a side opposite to the bearing inner space and the lateral face of the slinger on the side opposite to the bearing inner space are pressed at the same time.
Generally, in the hub seal, the interference between the side lip and the lateral face of the flat-plate portion of the slinger on the side of the bearing inner space is set such that the interference is an appropriate value when the end of the sealing member on the side opposite to the bearing inner space and the lateral face of the slinger on the side opposite to the bearing inner space are arranged on the same plane.
As a wheel bearing apparatus, a wheel bearing apparatus of a third-generation unit type including an attachment flange that is attached to a vehicle body and that is disposed on the vehicle inboard side of an outer ring member and including a wheel attachment hub flange disposed on the vehicle outboard side of a hub spindle serving as an inner ring member has been known. When the above-described hub seal is attached at an opening on the vehicle outboard side of the bearing inner space of the wheel bearing apparatus of the third-generation unit type, it is not possible to press the sealing member and the slinger from the vehicle outboard side at the same time to attach the sealing member and the slinger (see Japanese Patent Application Publication No. 2007-127243 (JP 2007-127243 A)).
In the step of assembling the hub seal attached to the vehicle outboard side of the wheel bearing apparatus of the third-generation unit type, the slinger is attached to the hub spindle in advance separately from the sealing member. However, in a structure in which the hub spindle has no means for restricting the position of the slinger in an axial direction, it is difficult to fix the slinger at an accurate position on the hub spindle in the axial direction. Therefore, an interference in the axial direction between the side lip and the slinger may be excessive or insufficient in the hub seal, and as a result, the sealing unit of the wheel bearing apparatus may not have sufficient sealing performance.